Do Carbs Matter After A Workout?

• A new RCT shows some compelling recovery benefits for carbs 

• What we know about glycogen depletion isn't the full story

• Learn what to tell athletes when they want to "train low," especially after HIIT workouts and when they have more sessions ahead

If you like what you see here, check out our board-approved continuing education courses. We cover topics like:

- Nutrition interventions for chronic diseases (e.g., obesity, diabetes, cardiovascular diseases)

- Advanced nutritional strategies to support physical therapy for patients with metabolic disorders

- Case studies demonstrating successful integration of nutrition into physical therapy care plans

Click here to get certified in Nutritional Physical Therapy!

Transcript:

Transcript:

Good morning, Dr. Wells here from Nutritional Physical Therapy. I got a cool research update. This is a good one for our sports PTs, some of our strength and conditioning coaches, athletic trainers, and even outpatient PTs. The publication was in Acta Physiology, the Oxford edition, 2024 of October, so just last month, hot off the press. Javier Diaz-Lara is the primary author. He's out of Toledo, Spain, one of my favorite places in Spain.

Along with some other colleagues from Australia. The title was, Does Delaying Carbohydrate Consumption After Exercise Impair Exercise Performance The Next Day? Cool thing about this is a double randomized controlled trial. In other words, and it's crossover too.

In other words, the people that get to try one variable also get to try the next variable, so you get to see a good comparison between the two. Total subjects were nine. The reason why the number is so low is that the study has to look at muscle glycogen. In order to look at muscle glycogen, the authors have to actually go in and do muscle biopsies, which can be really painful and hard to recruit for. Regardless, what the authors did, and it's interesting because right now there's a lot of debate about carbohydrate availability and whether we need it, whether we should push our athletes to not have a lot of carbohydrate availability for certain workouts. We talk a lot about that in our nutrition courses, particularly our third course.

The interesting thing with this is these authors took these nine active men. Average VO2 max is around 46. What they did is they did a high intensity interval training program. They effectively did cycling 10 sets of two minutes, 94% max power. They were pretty exhausted afterwards. After that, they then said, are we going to put them on a regular carbohydrate regime? That's in that three-hour post-exercise period.

They would get 2.4 grams of carbohydrates per kilogram of body weight. Or would they get a taste-matched non-caloric substitute, basically not allowing them to have carbohydrates in that three-hour window. What they did is then 24 hours after recovery, they repeated the bouts until exhaustion.

In other words, you're going to cycle for those two minutes as hard as you can as many times as you can with a one-minute break in between. What they found is those athletes that did get that carbohydrate meal within that three-hour window after the first bout, they were able to do 17 rounds of the high intensity interval training compared to those that did not get the carbohydrate. They only did 13 rounds.

So they were able to do four more rounds of high intensity exercise the next day. Interestingly, the rated perceived exertion was also better in those that had the carbohydrate three hours after that first bout of high intensity interval training. What does this mean? Well, it means that carbohydrates are essential for recovering, particularly from high intensity exercise.

We talk a lot about that in our courses. We talk a lot about the importance of carbohydrates for athletes, particularly in this current social media epidemic of everyone needs to be low-carb, everyone needs to be low-carb. I argue not necessarily.

Some people, it works for them, but obviously in this case, for high intensity athletes, it does impact their performance, particularly the next day. Interestingly, when the authors looked at the muscle biopsies of the athletes, their overall muscle glycogen wasn't that low. However, when you dive into the data, what they suggest is they were doing total muscle glycogen. And what they suggest is that because this was a higher intensity exercise, the other data points have shown that type two muscle fibers, like from doing squats and deadlifts tend to use that muscle glycogen up faster. And so there are certain areas within the muscle that muscle glycogen might be used more, for instance, in the intra myofibular space versus the extra myofibular space. And so in other words, they were suggesting that the muscle glycogen might be depleted in one area of the muscle more than another area.

And they just basically did a larger test of overall muscle glycogen, which was lower, but just not statistically lower. So all this to be said, there's more research that needs to be done, but what we need to look at as physical therapists is encouraging our athletes after high intensity interval training is to get those carbohydrates, protein, get food right within that three hour window after exercise, particularly if they're going to go hit the gym or the field again the next day. Hope you like this information.

Get Certified in Nutritional Physical Therapy, earn your CNPT and CEUs